feat(WebServer): Add support for JavaScript modules

[cosstab]

Description of Change

Added media type for .mjs files on the WebServer library.

Previously, they were being served with the "application/octet-stream" MIME type, which web browsers wouldn't accept.

I chose "text/javascript" for the media type instead of "application/javascript" (which is used by the library for .js files) because the latter was deprecated on RFC 9239.

Test Scenarios

Tested on Arduino-esp32 core v3.2.1 using an ESP32 board.

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[github-actions]

Warnings

⚠️

Some issues found for the commit messages in this PR: the commit message "feat(WebServer): Add support for JavaScript modules": scope/component should be lowercase without whitespace, allowed special characters are _ / . , * - . Please fix these commit messages - here are some basic tips: follow Conventional Commits style correct format of commit message should be: <type/action>(<scope/component>): <summary>, for example fix(esp32): Fixed startup timeout issue allowed types are: change,ci,docs,feat,fix,refactor,remove,revert,test sufficiently descriptive message summary should be between 10 to 72 characters and start with upper case letter avoid Jira references in commit messages (unavailable/irrelevant for our customers) TIP: Install pre-commit hooks and run this check when committing (uses the Conventional Precommit Linter).

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Generated by 🚫 dangerJS against 8e609cf

[github-actions]

Test Results

 76 files   76 suites   13m 12s ⏱️
 38 tests  38 ✅ 0 💤 0 ❌
241 runs  241 ✅ 0 💤 0 ❌

Results for commit 8e609cf.

♻️ This comment has been updated with latest results.

[github-actions]

Memory usage test (comparing PR against master branch)

The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.

Memory	FLASH [bytes]		FLASH [%]		RAM [bytes]		RAM [%]
Target	DEC	INC	DEC	INC	DEC	INC	DEC	INC
ESP32C5	0	0	0.00	0.00	0	0	0.00	0.00
ESP32P4	0	0	0.00	0.00	0	0	0.00	0.00
ESP32S3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32S2	0	0	0.00	0.00	0	0	0.00	0.00
ESP32C3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32C6	0	0	0.00	0.00	0	0	0.00	0.00
ESP32	0	0	0.00	0.00	0	0	0.00	0.00

Click to expand the detailed deltas report [usage change in BYTES]

Target	ESP32C5		ESP32P4		ESP32S3		ESP32S2		ESP32C3		ESP32C6		ESP32
Example	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM
libraries/WebServer/examples/AdvancedWebServer	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/FSBrowser	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/Filters	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HelloServer	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HttpAdvancedAuth	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HttpAuthCallback	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HttpAuthCallbackInline	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HttpBasicAuth	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HttpBasicAuthSHA1	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/HttpBasicAuthSHA1orBearerToken	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/Middleware	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/MultiHomedServers	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/PathArgServer	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/SDWebServer	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/SimpleAuthentification	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/UploadHugeFile	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/WebServer	-	-	-	-	-	-	-	-	-	-	-	-	-	-
libraries/WebServer/examples/WebUpdate	-	-	-	-	-	-	-	-	-	-	-	-	-	-